ICI 204,636, a novel, atypical antipsychotic: early indication of safety and efficacy in patients with chronic and subchronic schizophrenia.

We evaluated the effects of ICI 204,636 in 12 hospitalized patients with schizophrenia in a double-blind, placebo-controlled, parallel-group, rising-dose study. Patients met the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria for chronic or subchronic schizophrenia and had a total score > or = 30 on the 18-item Brief Psychiatric Rating Scale (BPRS) and a score > or = 3 on the Clinical Global Impression (CGI) Severity of Illness item. Patients received 21 days of double-blind treatment with increasing doses of ICI 204,636 (25 to 250 mg/d) or placebo. Efficacy was assessed using the BPRS and CGI. Response to treatment was defined as a > or = 30% decrease in the BPRS total score from baseline. Extrapyramidal symptoms and abnormal involuntary movements were assessed using the Simpson Scale and Abnormal Involuntary Movement Scale. Changes from baseline in the BPRS and CGI were significantly greater at end point for patients who received ICI 204,636 versus placebo (BPRS, -20.9 vs -4.8; CGI, -2.9 vs -1.0; P < 0.05, analysis of covariance; P < or = 0.06, Wilcoxon rank sum test). All patients in the ICI 204,636 group responded to treatment (P < 0.10) versus only two patients in the placebo group. Mild somnolence occurred in 50% of ICI 204,636-treated patients. No treatment-emergent extrapyramidal symptoms or dystonic reactions were observed. ICI 204,636 showed efficacy in the positive and negative symptoms of schizophrenia and was well tolerated.